Nitrogen and Phosphorus Uptake Dynamics in Tropical Cerrado Woodland Streams

Author(s)

Finkler, Nicolas Reinaldo ^[1] ; Tromboni, Flavia ^{[2, 3]} ; Boechat, Iola Goncalves ^[4] ; Gucker, Bjorn ^[4] ; Fernandes Cunha, Davi Gasparini ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Hydraul & Sanitat Engn, BR-13560590 Sao Carlos, SP - Brazil

^[2] Univ Nevada, Dept Biol, Reno, NV 89557 - USA

^[3] Univ Nevada, Global Water Ctr, Reno, NV 89557 - USA

^[4] Univ Fed Sao Joao del Rei, Dept Geosci, BR-36301360 Sao Joao Del Rei, MG - Brazil

• Document type: Journal article
• Source: WATER; v. 10, n. 8 AUG 2018.
• Web of Science Citations: 2

Abstract

Pollution abatement through phosphorus and nitrogen retention is a key ecosystem service provided by streams. Human activities have been changing in-stream nutrient concentrations, thereby altering lotic ecosystem functioning, especially in developing countries. We estimated nutrient uptake metrics (ambient uptake length, areal uptake rate, and uptake velocity) for nitrate (NO3-N), ammonium (NH4-N), and soluble reactive phosphorus (SRP) in four tropical Cerrado headwater streams during 2017, through whole-stream nutrient addition experiments. According to multiple regression models, ambient SRP concentration was an important explanatory variable of nutrient uptake. Further, best models included ambient NO3-N and water velocity (for NO3-N uptake metrics), dissolved oxygen (DO) and canopy cover (for NH4-N); and DO, discharge, water velocity, and temperature (for SRP). The best kinetic models describing nutrient uptake were efficiency-loss (R-2 from 0.47-0.88) and first-order models (R-2 from 0.60-0.85). NO3-N, NH4-N, and SRP uptake in these streams seemed coupled as a result of complex interactions of biotic P limitation, abiotic P cycling processes, and the preferential uptake of NH4-N among N-forms. Global change effects on these tropical streams, such as temperature increase and nutrient enrichment due to urban and agricultural expansion, may have adverse and partially unpredictable impacts on whole-stream nutrient processing. (AU)

• FAPESP's process: 16/14176-1 - Macronutrient retention in Cerrado streams (SP) and its relationships with aquatic metabolism along gradients of environmental conditions: an ecosystem services' approach
• Grantee: Davi Gasparini Fernandes Cunha
• Support Opportunities: Regular Research Grants